MAX1577Y Datasheet, PDF (1/11 Pages) Maxim Integrated Products – 1.2A White LED Regulating Charge Pump for Camera Flashes and Movie Lights

19-3461; Rev 0; 11/04
EVALUATION ^{KIT AVAILABLE}
1.2A White LED Regulating Charge Pump for
Camera Flashes and Movie Lights
General Description
The MAX1577Y/MAX1577Z charge pumps drive white
LEDs, including camera strobes, with regulated current
up to 1.2A (guaranteed to 800mA). The very low open-
loop output resistance allows high flash brightness,
even from a low battery input voltage. The adaptive
1x/2x regulating charge-pump operation provides high
efficiency (up to 92%) while in movie mode or back-
lighting. Fast (1MHz) switching allows the use of tiny
external components.
The MAX1577Y/MAX1577Z use an external resistor to
set the full-scale LED current. Two enable inputs (EN1
and EN2) provide simple on/off control and LED current
of 20%, 33%, or 100% full scale. If there is less than
24mV across the external resistor, the output voltage is
regulated. The MAX1577Z has fixed 5.1V output-volt-
age regulation, while the MAX1577Y has logic-con-
trolled output voltage of 3.4V, 4.6V, or 5.1V for
backlighting, keyboard, and RGB applications.
The MAX1577Y/MAX1577Z are available in an 8-pin,
3mm x 3mm TDFN package (0.8mm max height).
Applications
White LED Flashes, Strobes, and Movie Lights
LCD Backlighting
Camera Phones, Cell Phones, and Smart Phones
PDAs, Digital Cameras, and Camcorders
Features
♦ Up to 1.2A Output Drive Capability (800mA
Guaranteed)
♦ Up to 92% P_LED / P_BATT Efficiency for Movie
Mode
♦ Flexible Brightness Control
Two-Bit Logic for 100%, 33%, 20%, and Off
PWM for 20% to 100%
♦ 3% Current Regulation Over Line and
Temperature
♦ Current or Voltage Regulation for Flash and
Backlighting (MAX1577Y)
♦ Current Regulation for Flash (MAX1577Z)
♦ Low Ripple and EMI
♦ 2.7V to 5.5V Supply Voltage Range
♦ Soft-Start Limits Inrush Current
♦ Output-Voltage Regulation Mode
♦ Thermal-Shutdown Protection
♦ 8-Pin 3mm x 3mm TDFN Package
Ordering Information
PART
MAX1577YETA
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
8 TDFN
(T833-2)
TOP
MARK
AMG
MAX1577ZETA
-40°C to +85°C
8 TDFN
(T833-2)
AMQ
Typical Operating Circuit
1µF OR 2.2µF
CP
2.7V TO 5.5V
IN
4.7µF
GND
CN
5.3V OVP
OUT
10µF
UP TO 1.2A
100%,
33%, 20%,
AND
SHUTDOWN
MAX1577Z
EN1
CS
V_OUT - (300mV OR
100mV OR 60mV)
EN2
TOP VIEW
Pin Configuration
8
7
6
5
MAX1577Y
MAX1577Z
1
2
3
4
TDFN
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.